1. Field of the Invention
The present invention relates to a cone type twin screw extruder.
2. Description of the Related Art
There has been known such a bone type twin screw extruder as disclosed in Japanese Patent Publication No. HEI 1-30610 and Japan Utility Model Publication No. HEI 1-21787.
In the cone type twin screw extruder, two rotor shafts are disposed in such a manner as to taper to a smaller size toward their leading edge and to be rotatable, and an interlocking device is provided on the side of the base portion of the rotor shafts for interlockingly connecting the rotor shafts with each other. In the type described in Japanese Patent Publication No. HEI 1-30610, the above interlocking device comprises bevel gears which are provided on the base portions of the rotor shafts and are meshed with each other. Further, in the type described in Japan Utility Model Publication No. HEI-1-21787, the interlocking device comprises a pair of worm reduction gears provided on the base portions of the rotor shafts, and a belt transmitting device for interlocking connecting the worm shafts of the worm reduction gears.
The type of Japanese Patent Publication No. HEI 1-30610 is disadvantageous in that a pair of the bevel gears are large in size and cannot be machined without a special large sized gear cutting machine, resulting in increased cost.
Further, the type of Japan Utility Model Publication No. HEI 1-21787 is disadvantageous in that, since it uses the worm reduction devices, the power transmission efficiency is lowered to be about 70%, resulting in high energy loss.